I just installed the KDE version of Linux Mint 18.2. I was looking into installing and testing out LXQt, and was happy to see there are packages and a meta-package in the default repositories. However, when I try to install it I get the below result. This isn't very descriptive, I was hoping for a reason as to why the dependencies won't be installed. Any ideas?

$ sudo apt-get install lxqt
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
lxqt : Depends: lxqt-core (= 4) but it is not going to be installed
Depends: lxqt-about but it is not going to be installed
Depends: lxqt-admin but it is not going to be installed
Depends: lxqt-config but it is not going to be installed
Depends: lxqt-globalkeys but it is not going to be installed
Depends: lxqt-notificationd but it is not going to be installed
Depends: lxqt-openssh-askpass but it is not going to be installed
Depends: lxqt-policykit but it is not going to be installed
Depends: lxqt-powermanagement but it is not going to be installed
Depends: lxqt-qtplugin but it is not going to be installed
Depends: lxqt-runner but it is not going to be installed
Depends: lxqt-sudo but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

No doubt there's a clash with KDE packages which is why it's not recommended to install secondary desktops on Mint. I read in a thread that if you want to install a new desktop environment you are best off starting with a Mint XFCE base, so you might wish to pursue that avenue.

Installing more than one DE is just a bad idea anyway. Installing it over Xfce would likely give you problems too, you just wouldn't have been warned. Multiple DEs are a great way to break your system.

MintBean wrote:No doubt there's a clash with KDE packages which is why it's not recommended to install secondary desktops on Mint. I read in a thread that if you want to install a new desktop environment you are best off starting with a Mint XFCE base, so you might wish to pursue that avenue.

It's funny, because I installed the KDE version thinking that both being dependent on Qt would reduce the number of packages needed. But upon reflection it makes sense that they may not be in sync with their Qt requirements. To be honest, I'm pretty blown away with the latest versions of KDE, it's a lot better than I remember it, responsive, attractive, and gets out of the way. It doesn't even seem to use up too many resources on my old laptop. I'll probably stick with it for now.

Hoser Rob wrote:Installing more than one DE is just a bad idea anyway. Installing it over Xfce would likely give you problems too, you just wouldn't have been warned. Multiple DEs are a great way to break your system.

I get what you're saying, but that seems a little bizarre and quite different from most of the ways I've used linux over the years. At work now we have KDE and Gnome, and you can choose between them. But I can see how DEs that use the same underlying libraries (eg. XFCE and Gnome or LXQt and KDE) might have problems. The area I've noticed lately where I think you're right is in managing network connections, which is really frustrating to me how much that seems to now be tied to custom packages within each DE.

$ apt install libqt5xdg1
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
libqt5xdg1 : Depends: qtbase-abi-5-5-1

So, it's sort of a conflict with Kubuntu PPA which is used in Mint KDE (besides Kubuntu itself).

They provide a newer version of libqt5core5a than in Ubuntu repos. That version provides qtbase-abi-5-6-1 instead of qtbase-abi-5-5-1 (both are virtual packages). But LXQt needs the older version as it's built against the packages from the original Ubuntu repos.

Monsta wrote:I tracked it down to this:
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So, it's sort of a conflict with Kubuntu PPA which is used in Mint KDE (besides Kubuntu itself).

They provide a newer version of libqt5core5a than in Ubuntu repos. That version provides qtbase-abi-5-6-1 instead of qtbase-abi-5-5-1 (both are virtual packages). But LXQt needs the older version as it's built against the packages from the original Ubuntu repos.

Wow, great detective work, thanks! Now that I know I shouldn't use multiple DE's I'm fine using KDE for the moment. I'll consider LXQt at some point in the future when I get bored with KDE.